Monday, October 15, 2018

Geoclue 2.5 & repeating call for help

Just wanted to announce release 2.5.0 of Geoclue that includes the changes I mentioned in my last blog post.

Also, while I'm at it, I wanted to highlight the "call for help" at the end of that post by repeating it here again. I apologize of repeating to those who already read it but a friend pointed out that it's likely going to be missed by many folks:

The future of Mozilla Location Service

When Mozilla announced their location service in late 2013, Geoclue became one of its first users as it was our only hope for a reliable WiFi-geolocation source. We couldn't use Google's service as their ToC don't allow it to be used in an open source project (I recall some clause that it can only be used with Google Maps and not any other Map software). Mozilla Location Service (MLS) was a huge success in terms of people contributing WiFi data to it. I've been to quite a few places around Europe and North America in the last few years and I haven't been to any location, that is not already covered by MLS.

Mozilla's own interest in this service was tied to their Firefox OS project. Unfortunately Firefox OS project was abandoned two years ago and Mozilla lost its interest in MLS as a result. Mozilla folks are the good guys so they have kept the service running and users can still contribute data but it's no longer developed or maintained.

Since this is a very important service for all users of geoclue, I feel very uneasy about this uncertain future of MLS. So consider this a call for help. If your company relies on MLS (directly or through Geoclue) and you'd want to secure the future of Open Source geolocation, please do get in touch and we can discuss how we could possibly achieve that.

Sunday, September 23, 2018

Recently in Geoclue

After I started working for Collabora in April, I've finally been able to put some time on maintenance and development of Geoclue again. While I've fixed quite a few issues on the backlog, there has been some significant changes as of late, that I felt deserves some highlighting. Hence this blog post.

Leaving security to where it belongs


Since people's location is a very sensitive piece of information, security of this information had been the core part of Geoclue2 design. The idea was (and still is) to only allow apps access to user's location with their explicit permission (that they could easily revoke later). When Geoclue2 was designed and then developed, we didn't have Flatpak. Surely, people were talking about the need for something like Flatpak but even with those ideas, it wasn't clear how location access will be handled.

Hence we decided for geoclue to handle this itself, through an external app authorizing agent and implemented such an agent in GNOME Shell. Since there is no reliable way to identify an app on Linux, there were mixed reactions to this approach. While some thought it's good to have something rather than nothing, others thought it's better to wait for the time when we've the infrastructure that allows us to reliably identify apps.

Fast forward to an year or so ago, when Flatpak portals became a thing, I had a long discussion with Matthias Clasen and Bastien Nocera about how geoclocation should work in Flatpak. We disagreed on our approach and we forgot about the whole thing then.

Some months ago, we had to make app authorizing agent compulsory to plug some security holes and that made a lot of people who don't use GNOME, unhappy. We had to start installing the demo agent for non-GNOME as a workaround. This forced me to rethink the whole approach and after some more long discussions with Matthias and a lot of thinking, the plan is to:
  • Create a Flatpak geolocation portal. Matthias already has a work-in-progress implementation. I really wanted the portal API to be as identical to the Geoclue API but I failed to convince Matthias on that. This is not that big an issue though, as at least the apps using GeoclueSimple API will not need to change anything for accessing location from inside the Flatpak sandbox.
  • Drop all authorization from Geoclue and leave that to the geolocation portal. I've already dropped authorization for non-flatpak (i-e system) apps in git master. Once the portal is in place and GNOME shell and control-center have been modified to talk to it, we can drop all app authorizing code from Geoclue.

    that we have been able to reliably identify Flatpak apps and it's only the system apps that can lie about their identity.

A modern build system


Like many Free Software projects, Geoclue is also now using Meson for its builds. After it started to work reliably, I also dropped autotools-based build completely. The faster build makes development a much more pleasant experience.

And a modern issue tracker to go with it


Bugzilla served us well but patches in Bugzilla are no fun, even though git-bz makes it much much better. So when Daniel Stone setup gitlab on, Geoclue was one of the first few projects to move to gitlab. Now it's much easier and simpler to contribute to Geoclue.

Minimize GeoIP use


While GeoIP is a nice backup if you have neither WiFi hardware nor a cellular modem, Geoclue would also use (only) that if an app only asked for city-level accuracy. Apps like GNOME Weather and GNOME Clocks ask for only that since that's the info they need and don't need to know which street you're currently on. This would be perfect if only the GeoIP database being used would be correct or accurate for at least 90% of the IP addresses but unfortunately the reality is far from that. This meant, a significant number of people getting annoyed with these apps showing them time and weather of a different town than their current one.

On the other hand, we couldn't just use a more accurate geolocation source (WiFi) since an app should not get more accurate location it asked for and it was authorized for by the user. While currently we don't have the UI in GNOME (or any other platform) that allows users to control the location accuracy, the infrastructure has always been in place to do that.

Recently one person decided to not only report this but had a good suggestion that I recently implemented: Use WiFi geolocation for city-level accuracy as well but randomize the location enough to mitigate the privacy concerns. It should be noted that while this solution ensures that apps don't get more accurate location then they should, it still means sending out the current WiFi data to the Mozilla Location Service (MLS) and Geoclue getting a very accurate (street-level) location in response. It's all over HTTPS so it's not as bad as it sounds.

The future of Mozilla Location Service

When Mozilla announced their location service in late 2013, Geoclue became one of it's first users as it was our only hope for a reliable WiFi-geolocation source. We couldn't use Google's service as their ToC don't allow it to be used in an open source project (I recall some clause that it can only be used with Google Maps and not any other Map software). MLS was a huge success in terms of people contributing WiFi data to it. I've been to quite a few places around Europe and North America in the last few years and I haven't been to any location, that is not already covered by MLS.

Mozilla's own interest in this service was tied to their Firefox OS project. Unfortunately Firefox OS project was abandoned two years ago and Mozilla lost its interest in MLS as a result. Mozilla folks are the good guys so they have kept the service running and users can still contribute data but it's no longer developed or maintained.

Since this is a very important service for all users of geoclue, I feel very uneasy about this uncertain future of MLS. So consider this a call for help. If your company relies on MLS (directly or through Geoclue) and you'd want to secure the future of Open Source geolocation, please do get in touch and we can discuss how we could possibly achieve that.

Friday, May 18, 2018

Collabora and GStreamer spring in Sweden

Earlier this month, a few of us from Collabora, Olivier Crête, Nicolas Dufresne, George Kiagiadakis and I attended the GStreamer Spring Hackfest in Lund, Sweden. Hosted by Axis Communications (who uses GStreamer in their surveillance cameras for many years now), it was a great opportunity for the GStreamer community to touch base and work on open bugs and pet projects.

While I've been involved in the GStreamer project in the past, it was my first GStreamer hackfest. While a lot was achieved during the event, the most exciting outcomes were no doubt the closing of more than 350 bugs, and the agreement on a transition plan to move to GitLab.

Overall, the hackfest was very productive, with each member of our team managing to progress in their list of tasks while all taking part in bug triaging & cleaning in preparation of moving GStreamer's issue tracking to GitLab.

George spent time working on improving the new library API that is needed to introduce support for the non-interleaved audio layout, discussed a gst-rtsp-server issue with the Axis team, and merged all qt-gstreamer patches that were lying around in bugzilla and resolved all reported bugs, then declared it as unmaintained.

For his part, Nicolas participated in the planar audio format and split field interlaced video support work, started looking at adding per element latency tracing to GStreamer's existing latency tracer, and also discussed GStreamer CI, which will also move to GitLab to be able to run on pull requests also.

Olivier, during the first day, focused on the collective effort of reviewing all of the open bugs, managing to close a number of them while confirming and commenting on others. He also merged some outstanding patches he had (stay tuned for more details on those), and forward ported gst-validate for Android with the goal of running the CI on Android. He also merged a series of patches that enable bitcode embedding on the iOS target with the eventual goal of supporting tvOS as well.

As for myself, I mainly worked on (or rather started to work on) split-field interlacing support in GStreamer, adding relevant formats and modes in the GStreamer video library. In addition, as a Meson developer (Nirbheek Chauhan) was present, I took the opportunity to discuss with him the last bit of porting build system of Geoclue to Meson, a side project I've been working on. It helped me get it done faster but also helped Nirbheek find some issues in Meson and fix them!

All in all, my first GStreamer hackfest was an awesome experience (even though I was not feeling well). It was also very nice to hangout and socialize with old and new friends in the GStreamer community after a long time. Many thanks again to Axis for hosting us in their offices! See you at the GStreamer Conference this fall!

Monday, April 2, 2018

Joining Collabora

Last Thursday was my last day at Kinvolk. While Kinvolk is a great company run by very nice and talented folks and I really hoped to work there for a very long time, unfortunately it turned out to be not the best fit for me.

While I am sad to leave, I am also very excited to join Collabora in their multimedia team. Today is my first day there. Since Collabora does not exist in Germany, I will be working for them as a consultant and had to register my own one-man company. Yes, I will be staying in Berlin and work from home.

I have known Collabora from its very early days, when it was just a few developers with a vision and passion for Open Source. I also worked very closely with Collabora over the years during the good old Nokia Maemo/Meego times. I always had great appreciation for their work and commitment to Open Source, which is a huge challenge for a consulting company.

While I do not yet know which specific projects I will be involved in at Collabora, I'm most likely going to be working on/with GStreamer again and I'm especially excited about that. Also exciting for me is the fact that people at Collabora share my appreciation for the Rust programming language.

Wednesday, December 27, 2017

My journey to Rust

As most folks who know me already know, I've been in love with Rust language for a few years now and in the last year I've been actively coding in Rust. I wanted to document my journey to how I came to love this programming language, in hope that it will help people to see the value Rust brings to the world of software but if not, it would be nice to have my reason documented for my own sake.

When I started my professional career as a programmer 16 years ago, I knew some C, C++, Java and a bit of x86 assembly but it didn't take long before I completely forgot most of what I knew of C++ and Java, and completely focused on C. There were a few difference reasons that contributed to that:
  • Working with very limited embedded systems (I'm talking 8051) at that time, I quickly became obsessed with performance and C was my best bet if I didn't want to write all my code in assembly.
  • Shortly before I graduated, I got involved in GStreamer project and became a fan of GNOME and Gtk+, all of which at that time was in C. Talking to developers of these projects (who at that time seemed like gods), I learnt how C++ is a bad language and why they write everything in C instead.
  • An year after graduation, I developed a network traffic shaping solution and the core of it was a Linux kernel module, which as you know is almost always done in C. Some years later, I also wrote some device drivers for Linux.
The more C code I wrote over the years, the more I developed this love/hate relationship with it. I just loved the control C gave me but hated the huge responsibility it came with. With experience, I became good at avoiding common mistakes in C, but nobody is perfect and if you can make a mistake, you eventually will. Another reason C didn't seem perfect to me was the lack of high-level constructs in the language itself. Copy&pasting boilerplate to write simple GObjects is nothing most people enjoy. You end up avoiding to organise your code in the best way to spare yourself the trouble of having to write GObjects.

So I've been passively and sometimes actively seeking a better programming language for more than a decade now. I got excited about a few different ones over the years but there was always something very essential missing. The first language I got into was Lisp/Scheme (more specifically Guile) but the lack of type declarations soon started to annoy me a lot. I felt the same after then about all scripting languages, e.g Python. Don't get me wrong, python is a pretty awesome language for specific uses (e.g writing tests, simple apps, quick prototyping etc) but with lack of type declarations, any project larger than 1000 LOCs can quickly become hard to maintain (at least it did for me).

Because of my love for strong-typing, C# and Java did attract me too briefly. Not having to care about memory management in most cases, not only helps developers focus on the actual problems they are solving, it indirectly allows them to avoid making very expensive mistakes with memory management. However, if developer is not managing the memory, it's the machine doing it and in case of these languages, it does that at run time and not compile time. As a C developer and a big hater of waste in general, that is very hard to be convinced of as a good idea.

There was another big problem all these high-level languages: you can't nicely glue them with the C world. Sure you can use libraries written in C from them but the other way around is not a viable option (even if possible). That's why you'll find GNOME apps written in all these languages but you will not find any libraries written in them.

Along came Vala

So along came Vala, which offered features that at that time (2007-2008) were the most important to me:
  • It is a strongly-typed language.
  • It manages the memory for you in most cases but without any run time costs.
  • It's high-level language so you avoid a lot of boilerplate.
  • GNOME was and still is the main target platform of Vala.
  • It compiled to C, so you can write libraries in it and use them from C code as if they were written in C. Because of GObject-introspection, this also means you can use them from other languages too.
Those who know me, will agree that I was die-hard (I'm writing this on Christmas day so that reference was mandatory I guess) fan of Vala for a while. I wrote two projects in Vala and given what I knew then I think it was the right decision. Some people will be quick to point out specific technical issues with Vala but I think those could have been helped. There two other reasons, I ultimately gave up on Vala. The first one was that the general interest in it started to decline after Nokia stopped funding projects using Vala and so did its development.


Hello Rust

But the main reason for giving up was that I saw something better finally becoming a viable option (1.0 release) and gaining adoption in many communities, including GNOME. While Vala had many good qualities I mentioned above, Rust offered even more:
  • Firstly the success of Rust is not entirely dependent on one very specific project or a tiny group of people, even if until now most of the development has been from one company. Ever month, you hear of more communities and companies starting to depend on Rust and that ensure it's success even if Mozilla was to go down (not that I think it's likely) or stopped working on it. i-e "it's too big to fail". If we compare to Vala, the community is a lot bigger. There are conferences and events happening around the world that are entirely focused on Rust and there are books written on Rust. Vala never came anywhere remotely close to that level of popularity.

    When I would mention Vala in job interviews, interviewers would typically have no idea what I'm talking about but when I mention Rust, the typical response is "Oh yes we are interested in trying that out in our company".
  • While Vala is already a safer language than C & C++, you still have null-pointer dereferencing and some other unsafe possibilities. Safety being one of the main focus of the language design, Rust will not allow you to build unsafe code, unless you mark it as such and even then, your possibilities of messing up are limited. Marking unsafe code as such, makes it much easier to find the source of any issues you might have. More over, you usually only write unsafe code to interface with the unsafe C world.

    This is a very important point in my opinion. I really do not want to live in a world where simple human errors are allowed cause disasters.
Admittedly, there are some benefits of Vala over Rust:
  • Ability to easily write GObjects.
  • Creating shared libraries.
However, some people have been working on the former and latter is already possible with some compromise and tricks.


Should we stop writing C/C++ code?

Ideally? Yes! Most definitely, yes. Practically speaking, that is not an option for most existing C/C++ projects out there. I can only imagine the huge amount of resources needed for porting large projects, let alone training existing developers on Rust. Having said that, I'd urge every developer to at least seriously consider writing all new code in Rust rather than C/C++.

Especially if you are writing safety-critical software (people implementing self-driving cars, militaries and space agencies, I'm looking at you!), laziness and mental-inertia are not valid reasons to continue writing potentially unsafe code, no matter how smart and good at C/C++ you think you are. You will eventually make mistake and when you do, lives will be at stake. Think about that please.



I am excited about Rust and I'm hopeful the future is much safer thanks to people behind it. Happy holidays and have a fun and safe 2018!

Friday, December 8, 2017

Moving to Berlin

I have been meaning to document my experience of moving to Berlin, mainly to help people who are considering to move or are about to move. However I'm lazy and unless I'm paid to do so, I just won't get around to doing that so instead of ending up posting nothing, I'll just quickly list all the advice I have here:

  • Don't actually order any services through check24 website. Only use them to compare prices etc.
  • Avoid Vodafone for broadband connection. Follow this thread for why.
  • Consider using an online bank, like N26.
  • For your Anmeldung,
    • go to Bürgeramt in Neukölln or Kreuzberg (unless you speak German).
    • book appointment around noon or be prepared to wait a month.
  • Make sure you have local friends who speak German and are willing to help you out. Many locals will tell you that you don't need German in Berlin but that is simply not true.
  • Either consider hiring an estate agent or make sure your temporary residence allows you to register on their address.
  • Related to above, you don't have to pay deposit upfront if you use EuroKaution service.
  • Consider the after 10am monthly travel pass if you don't commute to work before that time.

Monday, August 21, 2017

Ich bin ein Berliner

Well, no, not really but maybe I'll be able to claim that at some point because I'm moving to Berlin to join Kinvolk. I'm told that I'm changing countries and companies too often but that's not true. I was at Red Hat for 5 years and at Nokia before that for 5 years as well. The decision to move out of Finland was not exactly mine.

Regarding Pelagicore

I'm not as much leaving Pelagicore as I'm leaving the automotive industry, more specifically the software side of it. While the automotive industry is changing and mostly for the good, I realized that it still is not a place for me. Things typically move very slowly in this industry and I realized that I don't have the required patience for it. Also, C++/Qt are big here and while an year ago I thought it's just another language and Open Source UI framework, I no longer think so. Since you can find a lot of rants from very experienced C++ developers on why C++ is a horrible language, I won't rant about that in here.

My experience with Qt hasn't been that great either. Most of the documentation I found would simply assume you use Qt Creator and despite my years of experience with D-Bus, it took me weeks to figure out how to make a few D-Bus calls from Qt (I have to admit though that the calls involved complex types). While Nokia made Qt a normal Open Source project by relicensing it under LGPLv2, the Qt company recently realized that it's loosing a lot of money by people using Qt in products without paying them anything so they relicensed it under GPLv3 and commercial (i-e dual-license).  I maintained Genivi Development Platform for 6 months and because of this relicensing, we were unable to upgrade Qt 5.6 to Qt 5.7 and overtime it had been becoming a major pain point in that project. To make things even less open-sourcy, they require all contributors to sign a CLA. I believe (and I think many would agree) that CLAs are bad for Open Source. So all those things put together, I don't think of Qt as a typical Open Source project. Feel free to disagree but that's how I feel and hence I'm not keen on working with Qt in future.

Having said all that, Pelagicore is a very awesome company and probably the best place to be if you're fine with C++/Qt and want to be part of the next-gen automotive. It might sound like I just contradicted myself but not everyone thinks and sees the world like me. To each, his own and all. Also Pelagicore is hiring!

Why leave Gothenburg?

Gothenburg is a very lovely city and I'm going to miss it a lot for sure, even though I've been only here for an year. I still love the Swedish language, which I have been learning slowly over the year. However, I've not been happy with the cost of living in here, especially Veterinary costs. I have an old cat with multiple conditions so I need to visit the Vet every few months. The Vet charge 700 SEK just to see him and most often they don't even care to read through his records beforehand.

Gothenburg is also currently the best place to find an accommodation in. To get a first-hand contract, you register yourself in on Boplats website and keep on applying to new listings but typical wait-time is in years, not months or weeks. In practice, it's usually not a problem. Most people just get a second-hand contract or a room in a shared flat to start with and then look for a more permanent solution. However, add a cat into the picture and things get very difficult again.

Kinvolk comes along

Because of the reasons stated above, I've been looking for some exciting opportunities outside automotive world in some nice location. I had been focused on finding jobs that either involve Rust language or at least there were good chances of Rust being involved. Long story short, I ultimately got in touch with Kinvolk folks. I already knew the company's founders: Chris, Alban and Iago. They are very good at what they do and fun folks to hang out with.

While Rust is not a big part of work at Kinvolk currently, they (especially Chris) seem very interested in it. From what I know, main languages at Kinvolk are C and Go. I don't mind coding in C anyway and I've been missing the times when I did any kernel programming in it. I've no experience of Go but from what I hear, it's a pretty decent language.

So after interviews etc, when Kinvolk offered me a job, I couldn't resist accepting it. Berlin is an awesome city and it's hard to say "no" to moving there.

If you're looking for a great place to work at on Linux-related tech with some very competent Open Source developers, do consider applying at Kinvolk.


Talking of great companies to work at, I recently got in contact with some folks from Cellink. It's a biotech company based in Gothenburg, whose aim is to end animal testing. They plan to achieve this very noble goal through 3D printers that print human tissues. They already have 2 products that they sell to pharmaceutical companies in 30 countries across the globe. While they already have the bio and hardware side of things covered, they are looking to expand their software side of things now and to do that, they need good software engineers, especially ones with Open Source experience.

Here is a video of a very nice intro to their awesome work from their CEO, Erik Gatenholm.

So if you're an Open Source developer and either live in or willing to relocate to (especially) Gothenburg, Cambridge (USA) or Bay Area, please contact me and I can connect you to the right people. Alternatively, feel free to contact them directly. I only want to help these folks achieve their very noble cause.